Just One Yesterday
by JaydePhoenixAnarchy
Summary: Post season nine finale. Sam and Castiel search for Dean, who has become a demon. Castiel's grace has fade leaving him human. Dean begins to visit Cas without Sam knowing. The former angel knows it's wrong but he can't help himself around Dean. Destiel featuring Demon!Dean and human!Cas
1. Chapter 1

Just One Yesterday

Chapter One

Cas sits on the bed in Dean's old room, gazing around. Weapons still hang from the plain, yellow-beige walls Dean's weapons. And the sheets still retain a certain smell; Dean's smell.

Cas can still remember the day that Metatron told him that Dean was dead. He remembers returning to the bunker to find Sam in the basement broken and sobbing on the floor. It looked as if he had been trying to summon a demon. Cas later found out that he had, in fact, been attempting to make a deal with Crowley and save Dean.

"Sam!" Cas ran to his fallen friend, placing a comforting hand on his back.

"Cas." Sam says, his voice barely above a whisper. "It's Dean… He… I… I tried to… I was too late, Cas." He choked out. "I couldn't save him."

"Where is he?" Castiel asks shakily.

"In his room." The Winchester says. He collapses back onto the cold cement floor. His body wrecked by another sob. Cas runs up the stairs, maybe he can still save him. He has enough grace left, just enough.

Upon entering Dean's room Cas is surprised to find Dean sitting on the edge of the bed staring blearily around. There was blood on his face and on his clothes, but his wounds appeared to have healed. He turns to Cas. "I can see you." He shakes his head.

"Dean…" Cas trails off, cocking his head to one side in confusion.

"You're so bright Cas. But you're fading, every second you're fading. What's happening to you Cas?"

"Dean you were…" Cas trails off, his voice cracking.

"I remember…" He trails off. "Metatron… he… He killed me didn't he?"

"Dean, how are you alive?" Cas asks.

"I don't know…" He licks his lips. "It's not the first time though right?" He half smirks, a familiar gleam in his eyes. "Ugh. My head." He massages his temples, squeezing his eyes shut.

"Dean!" Cas runs to the other mans side sitting down on the mattress beside him. "Are you alright?"

"Yeah. I just…" The other man looks up at him, his eyes open and they are black. Cas stands stumbling backwards into the wall his blue eyes wide in shock.

"No." he slides slowly down the wall onto the floor, shaking his head. "No, no, no, no, no…"

"Cas!" Dean kneels beside him. He cups the angels face in his hands, his eyes green again and wide with worry. "What's wrong?"

"You don't…" Cas can't quite for proper sentences. "Not you. Anyone but you."

"Cas you're not making sense." Dean says. At that moment Sam comes though the doorway.

"Dean?" He says. "But you're…"

"Dead. I know." He says. "Been over that bit."

"But how are you…" He says.

"Alive?" He says. "No idea."

"What's wrong with him?" Sam gestures to Cas, who now has his face buried in his hands.

"That's what I'm trying to figure out." Dean growls. "He was fine a minute ago, and then he just freaked out."

"I should have seen…." Cas mutters. "My fading grace, it must have blinded me." He grabs handfuls of his own hair. "How did this happen?"

"How did what happen Cas?" Sam asks.

"The mark!" Cas looks up, his blue eyes suddenly wide with realization. " When you died the mark must have…"

Dean's eyes widen in understanding. "You think that I'm…" he chokes slightly, horrified. "No. No I can't be."

Sam looks back and fourth between the angel and his brother. Dean's shaking his head back and fourth, his eyes held shut. "Dean." Dean looks up at him, his eyes pitch black. "Dean, your eyes!" Sam exclaims.

"Sammy?" Dean says. "Help me."

"Dean we can fix this." Sam says. "We can cure a demon. We can save you Dean." His voice shakes.

"Okay." Dean agrees. "Do whatever you need to do, just help me… please."

"We will Dean." Cas wraps an arm around the other mans shoulders.

Cas laughs shakily to himself. How ignorant they had been. Thinking that Dean was like any demon. That he could be cured like any demon. So when they had tried to cure him and it hadn't worked, they quickly realized their mistake. Dean was a demon born of the mark of Cain himself, more powerful than any they had encountered before.

Dean's reaction to this had been an unexpected one. He had laughed, it was a cold bitter laugh like nothing Cas had ever heard from the man before.

"Well I guess that's it then." Dean ran his shaking fingers through his hair. "Guess I'm stuck like this."

"Dean, don't say that!" Sam had replied, there was still so much confidence in his voice, he was so sure of himself, even after the cure had failed. The problem was obvious, the mark had a hold on the righteous man's soul and it wasn't letting go without a fight. "We'll find a way, we always do!"

Dean smiled bitterly. "Not this time Sammy." His voice stayed steady but there was a deep sadness in his normally bright green eyes. And in the next second he was gone, he just disappeared, the way Cas used to do before Metatron stole his grace in order to make the angels fall.

They had spent the next few months either out searching for Dean or buried in research about the mark of Cain. Unfortunately they hadn't come up with much in either category. That was around the time that Castiel's stolen grace faded leaving him completely human.

It was also around the time that he started seeing Dean. The first time was when he was out picking up some groceries for Sam, he had seen his reflection in the glass of the window, and there behind him was Dean. When Castiel turned around however, no one was there. Then it had happened again while he was walking down a busy street, there Dean was standing there, cocky smirk, permanent sex hair and all, and then he was gone. There were a few more times after this, always the same, there one second, gone the next until finally Cas began to suspect he was going crazy.

And then it happened. Castiel had been out at the bar with Sam, celebrating a successful rugaru hunt. He swept his blue eyes over the crowd as he so often did. It had become a subconscious habit ever since he started seeing Dean. As his gaze wandered over the faceless mass they all began to blur together and he began to believe he would never find the one he sought out with such determination. But there he was standing near the emergency exit at the back of the bar. When Castiel's eyes met Dean's, a clash o blue and green, a small smirk formed on thick lips. Dean winked and then he was gone.

Suddenly Cas couldn't breathe, the room was too crowded, and the air was too thick. He needed to get out. The wink had served, as something similar to proof that Cas wasn't going crazy. It really was Dean. It had to be.

Castiel stood so suddenly that he almost knocked his chair over.

"Cas?" Sam looked up at him, his voice heavy with concern. "Are you alright?"

"I need to use the restroom." He said without taking his eyes off of the spot where Dean had just been. He didn't wait for a response, just took off, pushing through the crowded bar.

Cas stood by the sink, running his shaking hands through messy dark hair. He bent over the porcelain basin, splashing cold water on his face. _Get it together Castiel. _He tried to slow his rapidly beating heart. Looking up at his reflection he found himself staring into the piercing blue eyes of a disheveled looking man with mussed up hair and an overgrowth of stubble.

And behind that man was another. A man with dirty blonde hair that was messy in all the right ways. A man with glittering green eyes that Castiel considered to be the colour of spring. Cas whirled around, half expecting to find himself alone in the bathroom. He was surprised when he ended up looking at the smirking face of Dean Winchester, standing not three feet away from him.

The demons green eyes go black for a second. "Heya Cassy."

Castiel takes a step back, bumping into the sink. "Dean…" His voice is barely above a whisper.

"Oh don't look so shocked." Dean grins. "It's not like this is the first time you've seen me."

Cas' blue eyes go wide. "I thought…" He trails off.

"What?" Dean smirks. "You thought you were crazy?" He chuckles. "That was kind of the point."

"Well…" Dean's gaze travels around the room. "It was sort of like a little game." He must see the blank look on the other man's face, because he quickly elaborates, "Y'know, see how long it took to crack you." He pauses, his green eyes glinting mischievously. "What I found the most interesting is that you never told Sam about me. Why is that Cas? You like having me as your dirty little secret?"

"I…" Cas trails off. Why hadn't he told Sam? That was a question that even the fallen angel himself could not answer. Instead he chose to change the subject. "Why are you following me Dean?" His voice shakes more than he'd like it to.

"Technically you and Sammy were the ones following me." He replies with a smug smile.

"We were looking for you Dean." Castiel begins. "We wanted to-"

"Yeah about that." Dean cuts him off. "That needs to stop. Real pain in my ass."

"Is that why you're here?" Cas inquires. "To tell us to stop searching for you?"

"That's part of it." Dean licks his lips, his green eyes raking over Cas in a way that makes him feel a bit like a bug under a microscope.

"Wouldn't it be more logical to tell that to both Sam and myself." Cas tilts his head to the left side in curiosity.

"Like I said before," Dean eyes darken with something Cas can't quite put his finger on. "There's another reason why I'm here."

The dark-haired man frowns. "What other reason could you have?"

The demon laughs. It's not the deep, full laugh that customarily belongs to Dean Winchester. It's a cold harsh sound that makes every hair on Cas' body stand on end. "You just don't get it do ya Angel?" His voice is lower than it had been previously.

The former angel could not understand what Dean meant by this. He opened his mouth to respond, but promptly closed it again.

Suddenly Dean disappears, reappearing a few seconds later with hi face mere inches away from Castiel's. The shorter man wishes he could move back, but finds himself already pressed up against the sink. Instead he finds himself trapped, staring up into the cold green eyes of the monster that had once been his friend.

The demon leans in, his warm breath tickling Cas' ear and sending shivers down his spine. "You're my favourite toy." His lips brush the skin for a second and then he's gone, leaving Cas pressed up against the sink, breathing heavily.

That was the last time Cas saw Dean, but even months later the words still lingered in his mind. _You're my favourite toy…_ What did Dean mean by that? Cas was pretty sure that he was a human and not an inanimate object.

Castiel sighed. After that he had started avoiding leaving the bunker whenever he could until he eventually began to stop going out altogether. The fear of having another encounter similar to the last was too much to handle. Four months had passed since then and still he could not forget the way Dean had looked at him… almost hungrily. The fallen angel shuddered involuntarily at the memory.

He was alone now for the most part. Sam was always off chasing another lead in his crusade to find and cure his monstrosity of a brother. Sometimes when Sam was gone, Cas would sleep in Dean's room, the smell of the pillow reminded him of the man he had fallen for.

Castiel stood, deciding that he might as well take a shower. He grabbed a towel from the supply closet and headed towards the bathroom.

Standing under the stream of hot water, Castiel allows his mind to wander. Ever since he became human the shower had become a place of comfort and safety for him. He would find himself taking extraordinarily long showers, just letting it wash over him. The water pressure in the bunker was phenomenal.

Cas step out of the shower, toweled himself off and the quickly dressed into a pair of worn jeans and one of Dean's old band shirts. He often wore Dean's old clothes; it was easier then buying the now human Cas an entire new wardrobe, and Dean didn't need them anyways. Not anymore.

Upon exiting the steam filled bathroom Castiel found that it was quite cold in the bunker and quickly headed back to Dean's room to grab a sweater. He picked a dark grey hoodie from the back of the closet and threw it on. Upon turning around he realized that he had made the bed, normally this wouldn't be a problem but Sam would be home either tonight or tomorrow and Cas didn't want the hunter to know that he had taken to sleeping in his brother's old bedroom. It was bad enough that he was wearing his clothes.

As Castiel spread the blanket over the bed he felt a slight prickling on the back of his neck, as if he was being watched. He shook his head, trying to shake off the feeling. It was impossible; very few people knew the location of the bunker and he was completely alone. And yet he could not shake it.

As he bent over, his back to the door, to place a pillow in its correct spot he heard a sharp intake of breath, similar to a hiss, from behind him. He whirled around to see none other than Dean Winchester slouching in the doorway biting his lip absentmindedly. "Not a bad view there, Angel. Are those my jeans?" He winked. Cas frowned, not quite understanding what the blonde man had meant by that.

"Dean-" He began, but the demon cut him off.

"Oh, that's right." He begins to walk, at a slow leisurely pace, across the room. "You're not an angel anymore are you Cassy? No. You're just a puny, pathetic _human._" He spits the last word as if it is something disgusting.

The words sting Cas, and he opens his mouth to respond but Dean isn't finished.

"It's funny seeing you like this y'know?" He smirks. "I remember there was a time when I was scared of you." He continues moving forward and Castiel takes an involuntary step back in spite of himself. "Now who's scared of who?" Dean raises his eyebrows.

"Why are you here Dean?" Cas forces his voice not to shake. Dean's right. He is powerless, and Dean on the other hand is more powerful than any demon they've encountered before. He could kill Cas in a second if he wanted to.

"Technically this is still my room." Dean smirks. "I got just as much right to be here as you do if not more so."

"Why don't you just come back Dean?" Cas asks, his voice pleading. "Sam and I have been researching the mark and we think there might be a way to-"

"To what Cas?" Dean's voice turns to something low and deadly. "To cure me? Did you ever think that maybe I don't need to be _cured? _Maybe there's nothing really wrong with me at all. Maybe I'm happier this way." He moves closer glaring at the dark-haired man. "Hell, I'm better of a demon. I'm stronger, faster, and infinitely more powerful than I was before. It's not blood pumping through my veins anymore it's raw energy that I can tap into whenever I like. Do you have any idea what that feels like?" He suddenly smiles evilly. "Of course you do. You used to be all hopped up on angel juice all the time. I finally understand why you did it. Why you cut that angels throat and stole his grace. You missed that high you got, that constant euphoria that you can only get from something like this. It was probably the same reason Sammy was so dependent on the demon blood. Power." Dean throws his head back in a laugh. "So you can take you're cure and shove it up your ass. Because as far as I'm concerned life's better this way."

"Dean, this isn't you talking." Castiel says.

"Now see that's where you're wrong Cas." The demon growls. "It's not like I've been possessed by anything. This really is me… In fact I'd say this is the real me."

Cas backs up again, now there is only about three inches of space between his back and the wall, nowhere to run. He could feel his hear pounding against his ribs.

"Look at you Cassy." Dean grinned. "You're shaking. Am I really that terrifying?"

Cas gulps, unable to form a proper response.

"Y'know one advantage to this whole demon thing?" Dean's green eyes darken he is standing less than a foot a way from Cas. "I can sense human emotions. And right now, there's fear coming off you in waves. It's…" He pauses, breathing deeply as if smelling the air. _"Intoxicating."_

Suddenly Dean slams his palms against the wall on either side of Castiel's head, glaring down at him with black eyes. "What's the matter angel? You afraid of the dark?"

Their eyes stay locked for a few seconds, and in that brief moment Cas' heart beats so loud that he's sure Dean can hear it.

And then the ex-hunter slams his mouth against Castiel's hard enough that the back of his head smashes against the wall behind him. At first the fallen angel doesn't know what to do, his hands push against Dean's chest but it doesn't do much good. And then he feels the other man's tongue sliding across his bottom lip and it awakens something primal inside him; some deep seated lust. The hands on Dean's chest tighten, grabbing fistfuls of his shirt as the dark-haired mans lips part allowing the taller man access to his mouth.

Dean nips at Castiel's lower lip eliciting a small moan from him. His hand slides up the shorter man's back, until it reaches the back of his head, then tangles in his hair. Without warning, the demon grabs a fistful of the messy dark locks and yanks Cas' head to one side. The former angel lets out a sharp gasp, and Dean chuckles and he presses his mouth to the smooth expanse of unblemished skin on his neck. He kisses ups the side then blows on the skin, smirking as Castiel shudders against him. He latches onto a spot near the fallen angel's throat, nipping and sucking at the skin and leaving a purple-red mark in his wake. He moves to another spot, then another, and another until Cas' neck is covered in bruise-like splotches, claiming the other man as his own.

Dean brings his mouth back up to Castiel's and the dark-haired man can't help but moan a little at the feel of Dean's lips on his once more. This isn't soft and tender like he'd always imagined kissing Dean would be, but it's enough. And Cas has wanted this for so long… needed it for so long, that he can't seem to bring himself to care all that much.

One of Dean's arms snakes around Cas' waist while the other slides up and tugs at the zipper on his sweater. With the sweater undone, Dean begins to shove it down Castiel's broad shoulders.

_No!_ The realization hits the former angel like a brick. This isn't Dean. Not his Dean. Not his righteous man. This is the monster that killed him. And he cannot let this happen! He digs into the pocket of his jeans and pulls out the tiny vial of holy water he keeps on him in case of emergencies. He pops off the lid and splashes onto the side of Dean's face.

Dean hisses and jumps back, his eyes are black. The look on his face is a combination of anger and confusion. "Cas, what the fuck?" He shouts. "I thought we were having fun!"

"Get out of here Dean." Cas spits.

Dean raises his eyebrows mockingly as his gaze roams over the flustered man before him. "Are you sure that's what you want?"

"Get. _The Hell. _Out!" The former angels tone is low and deadly.

"Fine." He shrugs. "But I'll be back." And with that the demon disappears.

Cas slumps back against the wall, panting and uncomfortably hard. He caught a glimpse of himself in the mirror and almost laughed at how ridiculous he looked. His dark hair was messier than he could ever remember it being and stuck up at odd angles. His face was red and his sweater was pushed halfway down his arms. Also it appeared that Dean had somehow managed to get the first three buttons on his shirt down without him noticing. And of course there was also the state of his neck, it was completely covered in small bruise-like marks. What was it humans called them? Hickeys? What a strange word.

Castiel sighed heavily. He was going to need another shower… a cold one.

After his second shower of the day Cas began searching for a way to cover up the marks on his neck. Upon digging through the old clothes left behind by the men of letters he found several turtlenecks, enough to last him through the next few days or at least until the bruises had faded.

After that he spends the rest of the day doing research, or trying to, he finds it difficult to focus when all he can think about is Dean. Dean's soft, full lips being pulled up into a cocky smirk before they pressed against his own. Dean's bright green eyes, and the way they turned to black. Dean's perfect teeth nipping lightly at the skin of his neck between kisses, leaving tiny red marks behind. Dean's calloused hands running over his body. Dean, Dean, Dean, DEAN! He couldn't get the demon out of his head and it was killing him. He put his fingers to his lips, still remembering the pressure of the other man's mouth on his. Why had Dean kissed him? It had to be some sort of twisted game… right?

By the end of the day he's spent hours attempting to do research with nothing to show for it. Sometimes he hated human emotions, they were distracting and frivolous. He missed the simplicity of being an angel. He had felt emotions; they were just not nearly as powerful as what he felt as a human.

At about ten thirty Castiel realized that it was doubtful he would be seeing Sam again today, and he was exhausted. He walked back to his room, his room this time because he wasn't sure if Sam would be back before he woke up, and quickly changed into an old t-shirt and a pair of boxers. After that he turned off the light and crawled into bed wrapping himself up in the blankets and falling into the dark embrace of oblivion.

The next morning Castiel awoke to the sharp smell of fresh coffee and, after a brief investigation, found Sam in the bunkers kitchen looking half dead with exhaustion.

"Hello, Sam." Castiel nodded in greeting before sitting down across from the taller man.

"Mornin' Cas." Sam looked up, his eyes were shadowed and bloodshot, and it looked as though he hadn't shaved in a couple days. "Had any luck with research?"

Cas shook his head solemnly. "What about you, any new leads?" His voice cracked a little, he knew he should tell Sam that Dean had been there but he just couldn't get the words out.

Sam looked down at the table, his limp brown hair hanging in his tired eyes. Castiel took his silence as an answer.

They sat like that for a long time, both silently contemplating the wood grain of the table until the coffee maker beeped and Sam stood up to grab his mug. He turned to Cas. "You want some?"

Cas frowned at the dark liquid. "I don't… What does it taste like?"

Sam laughed, adding cream and sugar to his own mug. "Here." He held the mug out to Cas. "Try some."

Castiel took the mug from Sam's hand and sniffed it before taking a tentative sip. He frowned at the flavour. "It's strange…" He muses. "Slightly bitter. I'm not certain I like the flavour… And yet," he looks at Sam, his blue eyes wide, "I want more!"

Sam laughs. "That's coffee for ya." He pulls down another mug from the cupboard and hands it to the over-eager looking man beside him. "I didn't make you into an addict did I?"

Cas pours coffee into the mug, then begins to spoon in mountains of sugar. "To early to say." He cocks his head to one side. "Addictions develop over time correct?"

Sam grins, holding back a laugh. "Yeah, Cas. That's how it works." He pauses tipping his head to one side. "Are you wearing a turtleneck?"

Cas looks down at himself, his face reddening slightly. _Please don't let him figure it out. _"I uh…"He stammers. "It's been cold."

Sam stares at him for a few seconds, his brows furrowed in a questioning look and for a second Castiel doesn't dare to breath. But the tall man just shrugs. "Okay."

Cas lets out an inward sigh of relief. That was too close for comfort.


	2. Chapter 2

Just One Yesterday

Chapter two

It was two days later that Cas next saw Dean.

He awoke in his room around ten forty-five, to bright sunlight streaming in through the small window. He rolled out of bed and checked his neck in the mirror; the marks had faded but were still visible. He sighed; he'd have to wear another of those itchy gray turtlenecks again today. He grabbed a stack of clothes and headed to the bathroom for a shower. After his shower he dressed quickly, brushed his teeth, and prepared for a long day buried among the musty old books. It wasn't that he minded; he liked books, it was just that they'd been doing this for months now and found next to nothing.

He went into the library where he found Sam buried in research and quickly joined him. There they sat for hours, not speaking, just flipping through book. It was then that Castiel began to feel eyes on him. He looked around but saw no sign that anyone else was present. This went on for about ten minutes, Cas briefly searching the room now and again, then returning to his research. He began to believe he was imagining things.

The sound of a throat being cleared behind them made both men look up, their heads snapping around to the back of the room almost in sync. A tall, light-haired man steps out of the shadows, smiling smugly.

"Hey, guys." The demon grins, his gaze sweeping over the room. "Well doesn't this look…" He fumbles for a word. "_Boring_." He fakes a yawn.

"Dean…" Sam starts, his blue eyes wide. It's at that moment that Castiel remembers it has been almost a year since Sam last saw his brother.

"Heya, Sammy." Dean grins. He turns his attention to the former angel, his eyes darkening. "Cas." He smirks. "Nice turtleneck." He licks his lips causing Cas to shudder inwardly. Why did Dean have to look at him like that?

"What are you doing here?" Cas growls, his voice like fire.

Dean laughs. "You know, that used to be intimidating. Back when you had power. But now you're nothing but-" suddenly his head snaps back to Sam just in time to catch him sliding his hand across the desk, reaching for Ruby's knife.

For a moment the demons face changes into a mask of pure rage, but then he just smirks. "Won't work you know." His smirk grows into a smug grin as Sam's brows furrow in confusion. "I tried it, didn't work on Cain, so it won't work on me. We're one in the same." His lips twitch in what resembles a snarl. "So don't even try it." Sam opens his mouth to say something but Dean cuts him off. "I'm only here to talk so why don't you sit down." Sam doesn't move. "I said," Dean flicks his fingers throwing his brother backwards into the chair behind him, "_sit." _He turns to the other man. "You too Angel."

Cas glares at Dean, blue eyes like chips of ice. "No."

Dean takes a step closer, his head tilted to one side. "I'm sorry, I don't think I heard that right." His tone is low and deadly. "I said. Sit. The _fuck._ Down." He punctuates each word, with a menacing step forward.

"And I said no." Cas spits, straightening up, but in truth his heart pounds in his chest and he's sure Dean can hear.

Dean steps so close that Cas can smell the sulphur on his breath. The demons eyes are like green fire, and his jaw clenches. For a minute Castiel thinks Dean might kill him, but then he just shrugs, stepping back. "Fine." He turns away and the dark-haired man releases a breath he didn't realize he'd been holding. Then Dean's left arm shoots out to the side, and Castiel is flung into a bookshelf. He collapses to the ground, staring up with wild eyes.

Sam stands, but Dean sends him sprawling backwards with a flick of his wrist before turning around to face them once more his eyes fading from black to green. "Now that wasn't so hard, was it?" He runs his fingers through his dirty blonde hair in exasperation. "Now, I didn't come hear just to slam your sorry asses against walls. I came to talk."

"Talk about what exactly?" Sam spits at his brother.

"Well the two of you," he points, "particularly you Sammy, have been a major pain in my ass for quite some time now. So here's how it's gonna play out, you two are going to stop this little crusade of yours and leave me the fuck alone. Alright?"

"No." Sam tries to stand but is thrown back down by a flick of his brother's wrist. "Dean, I know you're in there, the real you. And we can save you, I'm sure of it." Sam's eyes are wild with desperation.

"When will the two of you learn?" Dean grabs a handful of his sandy hair. "This is the real me, and deep down, I think you know that. I'm happy this way Sammy. It's that simple." The demon sighs. "Now look, I don't want to have to kill you, it's not really on my to-do list. But," his voice drops suddenly, his eyes going black, "if you continue to get in my way I will not hesitate to rip out your spleen." His eyes fade back to green. "Are we clear?"

The tall man glares at his brother for a long time and for a moment, Castiel is sure that Sam is about to do something very stupid. "Crystal." He spits in response.

"Good." Dean turns his attention to the other man, chewing his lip. "It was nice seeing you Cas." He winks and then disappears.

Cas tries to stand but his entire body is shaking and sore. He misses being an angel, misses how little he experienced things like fear and pain. He misses being strong. He slumps back to the ground, ready to give up, to just lie there among the fallen books forever. But Sam, who has already pulled himself up and made his way over to Cas without him noticing, extends a hand to him.

"You okay man?" He asks, pulling the fallen angel up onto his shaking legs.

"Yes." Cas stammers. "I-I'm fine." He can't look Sam in the eye, not after all he's kept hidden from him. "Though I think I may be injured."

"Here, let me look at you." Sam checks the blue-eyed man over for injuries. "It doesn't look like anything is broken, just a couple of bruises." He laughs. "Then again I'm no doctor."

Castiel frowns, not quite understanding the reason behind Sam's laughter. "No, I believe if you were to choose any profession aside from your current one it would be a lawyer would it not?"

Sam smiles sadly. "Yeah." He touches a spot on Cas' forehead. "It looks like you got a cut here. Want me to help you clean that up?"

The dark-haired man touches the spot on his forehead, when he pulls his fingers away they are coated in a thin layer of sticky, vibrantly red blood. "No. I think I'll be fine." He says. "I can do it myself."

"Okay." Sam sighs. "I'll be here. More research to do."

Castiel himself was beginning to believe that Dean was a lost cause, but he knew that Sam would never give up on his brother, even if it were the death of him.

The fallen angel stared mournfully at his reflection. He looks terrible. His jaw has already begun to bruise and the cut on the right side of his forehead drips blood down into his eye. He wets a wad of toilet paper and dabs at the skin, wiping away the blood to reveal a mere scratch. It should heal in a few days, not as quickly as it would had he still his grace, but quickly nonetheless.

It was odd; the sense of vulnerability the small injury brought him. This human form was so weak compared to what he once was, so easy to kill. He hates it. Hates Metatron for stealing his grace, hates the angels for coming after him when he was human, hates Dean for having so much power over him. But mostly he hates himself. He was the one who let Metatron fool him; it's his fault the angels fell. But then he was given a second chance, a chance to live life as a human… and he messed that up too. He had chosen to cut another angels throat and steal his grace, and when that had finally faded it had almost killed him. And now here he was again, he had let Dean kiss him, kept it from Sam, and he'd enjoyed it. If Dean were to kiss him again, he wasn't so sure he'd be able to resist this time.

The next three days were spent reorganizing the bookshelf that Cas had crashed into and doing more fruitless research into the mark of Cain. Near the end of the third day, Sam left. Some werewolf hunt in Wisconsin, but Castiel knew that while he was there Sam would search for information on Dean's whereabouts, despite the demons threats, and there was nothing anyone could do to stop him.

That night Castiel slept in Dean's bed as he always did when Sam was away, wrapping himself up tightly in the blanket that always smelled of whiskey and old leather, the smell of Dean. Well before the sulphur that is. As he fell asleep he thought about that Dean, the righteous man who he had fallen for faster than he could've imagine, the man who had made his heart skip a beat just by looking at him. Even as an angel Castiel had known he was in love with Dean, perhaps he'd always known. Hester was right, from the moment he laid a hand on Dean in Hell, he _was _lost. Well lost to the angels, but to him it felt more like he had been found. Now he was lost.

Castiel found himself sitting on a park bench; it was an odd placement for such a bench, in the middle of a field of wildflowers stretching for miles in all directions, like an ocean of colour. He looked up at the sky, cloudless and crystal blue, the sun hanging high above and showering him in it's golden light, it reminded him a little of heaven. He turned to his left and found himself looking at something more beautiful than anything around him.

"Hey, Cas." Dean smiles, his green eyes shining the way they always used to.

"Hello, Dean." The dark-haired man responds solemnly. This is his Dean, not the demon, not even the Dean controlled by the mark of Cain. This is the real Dean Winchester; with eyes like spring and as many freckles as there are stars in the sky. With a smile that lights up the room, though Castiel rarely sees it anymore. This is the man he fell in love with. "I miss you." He says after a long silence.

"I know." Dean says sadly. "But I'm gone Cas. Hell, I'm dead, this is all in your head anyways." He rakes a hand through his hair. "I'm just a manifestation of your guilt. After all, it is your fault."

Castiel's blue eyes widen in shock. "What?"

Dean turns his head to face away from Cas, and as he does, the sky begins to darken with clouds. Dean laughs, cold and cruel, turning back to Cas. His face is beaten and bruised, and blood wells out of a wound in his chest. "Look at me Cas!" He stands; the flowers beneath his feet begin to wither, as do all the flowers in the field. "Look me in the eye and tell me you had nothing to do with this! If you hadn't been off working to save your angel buddies, the ones who tried to _kill _you, then you could've warned me about the mark! And to further that, there was still a chance, even just a small one, to save me. But you were too late Cas! Had you smashed that tablet just a few seconds earlier I would still be alive right now." He places his hands on the back of the bench, leaning in so his bloodstained face is just inches away from that of the fallen angel. His eyes go black. "Look at me! Look at what I've become! I'm a monster, and it's all your fault!" Lightening flashes behind Dean, followed shortly by a deep rumble of thunder.

"Dean…." Castiel's voice is barely above a whisper.

"No." Dean cuts him off. "We're done here Cas." He spits the man's name like some unclean thing. Then he turns to leave.

"Dean, wait." The dark-haired man calls after him, his voice cracking with desperation.

Dean keeps walking, slowly fading into nothing, leaving Castiel alone on the bench, and then it starts to rain, to pour actually, but the fallen angel does nothing, just sits there and lets the water wash over him. Waiting to wake up. Waiting for it all to end. Waiting for his life to finally be over.

Castiel awoke to the sound of his alarm clock blaring. _Beep. Beep. Beep. Beep. _Nine thirty. He rakes his shaking fingers through his dark hair, mussing it further. He drags himself to the edge of his bed, resting his head in his hands. Tears form in his blue eyes but he doesn't let them fall. He can't. He has to be strong; it's what Dean would've wanted.

He reaches under the bed and pulls out the bottle of Jack Daniels Dean always kept there. The bottle is still fairly full. He takes a swing, it burns going down but the burning is quickly replaced by a pleasant tingling. When he was an angel, it always took so long for alcohol to affect him, but now… Now he truly understood what people found so magical about the substance. It helped you forget all your troubles. He took another swig. Yes, he was beginning to see the appeal of such a thing as this.

Twenty minutes and half a bottle later, Castiel was lying on the floor, staring up at the ceiling. His head felt strange, foggy almost. He couldn't help but laugh to himself at what he must look like, lying there next to a half empty bottle, wearing only a t-shirt and boxers, his hair sticking up at odd angles, unshaven and unshowered. Not to mention it wasn't yet ten o'clock in the morning.

He's not sure how long he laid there, pleasantly numb, but he was so out of it that he didn't notice the presence of someone else in the room until he hears the sound of a throat being cleared.

He doesn't have to look to know who it is, but he does anyway, rolling his head to one side to look at the door. "Hello, Dean." He slurs, laughing at the irony of his use of that particular phrase.

Dean frowns at him. "Cas, are you… drunk?"

Cas stands, stumbling a little; he's dizzier than he thought he was. "Do you care?"

Dean smirks. "Not really. But it's only quarter past ten. Don't you think that's a little early?"

Cas shrugs. "Fuck it."

"Ooo!" Dean grins. "I like it."

Cas cocks his head to one side. "Like what?" He asks.

"This whole rugged, I could give a crap thing." His gaze wanders over Cas' body lingering momentarily on his rumpled boxers before flicking back up to his eyes. "I gotta say it's kinda sexy." He moves closer, now only about a foot away from the dark-haired man.

"Of course you would say that." Cas rolls his eyes. "Why are you here Dean?"

"I came to see you." He flashes a seductive grin that makes Cas' heart speed up. "We have… unfinished business."

"Do we?" Cas says mockingly. "And what might that be?"

Dean licks his lips. "Don't play dumb with me, angel." His low voice sends shivers down Cas' spine. "You know what."

Cas runs his hand over his face in an attempt to look exasperated, but he can feel his cheeks redden. "Is this going to be a regular thing with you now?"

"Only if you want it to." Dean rakes a hand through his sandy hair.

"And what if I do." Cas responds, surprised by his own words. What is he doing? This is a terrible idea.

"Cas." Dean raises his eyebrows. "Are you flirting with me?"

Cas shrugs. "I honestly haven't thought it through that far yet."

"Well," Dean steps forward so he's mere inches away from Castiel. "What are you thinking now?"

The dark-haired man licks his lips, his eyes wandering over the demon's well-muscled body. In all honesty he's not thinking much of anything, he can't, the blood isn't exactly flowing to his brain at the moment. He looks up at Dean, his blue eyes dark with lust.

Dean leans in, his lips a mere half inch from the other man's, "It's your move angel." He whispers. "What are you gonna do now?"

The words hang in the air for a few seconds before Cas can't help himself any longer. He grabs Dean by the lapels of his jacket pressing their bodies together as well as their mouths. Dean chuckles nipping at the dark-haired man's lower lip. Cas moans in response, rutting up against the taller man's denim clad thigh.

"Mmm…" Dean sighs against the other man's mouth, yanking a handful of dark hair. "Good boy." His hand other hand slides up the back of Castiel's shirt, nails digging into skin, eliciting small moans from his partner.

Cas slides his hands up Dean's chest and to his shoulders, pushing both his jacket and over shirt off in one fluid movement. Dean kisses and licks at the former angel's neck, latching onto the sweet spot just below his jaw. "Dean…" Cas gasps, barely able to form the word. He pushes on Dean's chest.

Dean pulls away, frowning for a second before realizing why the other man pushed him away. "Oh, that's right." He smirks. "You had quite the time trying to hide those lovebites from dear old Sammy last time, didn't ya Angel?"

Cas nods, still panting.

"Don't worry." Dean winks. "I know a few places I can mark up that Sam won't see." Before Cas has the chance to ask what he means, the demons hands are on the hem of his shirt and he yanks it over his head, his mouth going to the newly exposed skin immediately. He kisses at the fallen angels chest, twirling his tongue around the peak of his nipple, before moving back up and sinking his teeth into the meat of his shoulder. Cas yells out a moan, throwing his head back in a combination of both pain and pleasure.

"Oh, you like that do ya?" Dean looks up at Cas, his green eyes wide in mock innocence. Cas nods shakily. "Say it!" Dean's face is suddenly right next to Castiel's, his eyes black. "Tell me what you want!"

Cas licks his lips. "Bite me." He gasps.

"What was that?" Dean whispers. His breath is warm on the fallen angels ear.

"I said FUCKING BITE ME!" Cas yells.

"Now we're getting somewhere." Dean nips at Castiel's earlobe before biting down on the other shoulder, causing Cas' entire body to stiffen.

"DEAN!" He moans, his hands wrapping around the other man, pulling him harder against him.

Dean pulls away suddenly, shoving Cas backwards onto the bed. The dark-haired man falls back, limbs splaying out in all directions as he looks up at the demon looming over him. Dean's green eyes are dark with lust as his gaze roams over the man before him for a few brief seconds before he crawls across the bed towards the fallen angel, straddling him and roughly pressing their lips together.

Dean nips at Castiel's lower lip before grinding his hips down into him. Cas moans at the friction of the denim against his crotch. His hands push under the back of Dean's shirt, but the lighter-haired man pulls them away with a small tsking sound, before removing his shirt in one fluid movement before using one hand to pin Cas' wrists above his head.

Cas lets his eyes run over the newly exposed skin of Dean's torso. The tattoo on the left side of Dean's chest is gone now; he must have had it removed. It also appears that Dean has put on quite a bit of muscle tone over the past few months. Castiel suddenly can't help but imagine what it would feel like to run his tongue over the rippling muscles of that bare chest, to taste every inch of Dean's salty skin.

Dean releases Cas' wrists, positioning his arms on the mattress for support as he bends down to kiss the human once more. It's a brief, rough kiss lasting only a few seconds before Dean is trailing those perfect lips down the side of his neck to his exposed chest. He rolls his tongue around the peaked skin of Castiel's nipple causing the man to let out small whimpering moans. Dean's mouth moves further down, passing the dark-haired man's chest and sliding slowly down his stomach until he reaches the spot just above the waistband of his partner's boxers.

The blonde kisses and licks at that spot before moving to the curve of his hipbone, sucking at the skin there while the former angel slowly becomes unraveled beneath him.

"Fuck!" Cas moans as Dean bites down on his hip hard enough to leave a mark.

Dean smirks up at him, his green eyes glinting mischievously. "You know Cas, I never though you'd be so kinky." He kisses the red welt left behind by his teeth, not breaking contact with the former angels blue eyes for a second. He then makes his way back to the spot just above Castiel's waistband, his lips lingering there for a few seconds. Then in one quick movement, he runs his tongue from that spot all the way up to the place between the dark-haired man's collarbones, chuckling at the way Cas shudders beneath him. He moves his lips up the side of the man's neck and Cas can't help but let out a small moan at the way the stubble pulls at his skin.

Dean hovers, his face a mere half-inch away from Castiel's, smirking teasingly. Cas responds by pushing his head up and meeting Dean's thick lips with his own in a passionate, lust-filled kiss. Dean leans down into the kiss, pressing their bare chests together, skin sliding against skin.

Without warning Dean sits up, pulling Cas into his lap. His hands immediately go to the fallen angel's ass, sliding down the back of his boxers, nails digging into skin. Cas moans, resting his head against Dean's shoulder as he grinds his hips into the other man. The dark haired man kisses at the skin there, moving his lips down Dean's chest, trying to taste every inch of the man. Dean leans back on his arms, moaning and bucking his hips as Cas' teeth graze his nipple. Cas slides his hand down slowly fumbling with the button on Dean's jeans. His head isn't feeling any less foggy than it was earlier, but right now he can't focus on anything except for this. He _needs _this, and whether or not he'll regret it later doesn't matter.

He shifts his body off of Dean's lap, leaning down so he can undo the zipper with his teeth. He glances up at Dean to see the man staring down at him biting his lip, green eyes dark with lust. Cas pulls the zipper down the rest of the way to expose Dean's plain black boxers. Then he places his fingers under the waistband of the boxers and the jeans, pulling them down in one go and exposing Dean's throbbing member. He licks his lips at the sight of it.

Castiel leans down, flicking his tongue over the tip and Dean hisses at the touch. He takes the length in his mouth and begins slowly bobbing his head. He doesn't really know what he's doing but Dean doesn't seem to mind very much. He responds by grabbing a handful of the former angel's dark hair, pulling him down further. The sharp pain from the tug makes Cas moan a little, and the vibrations from that, in turn, cause Dean to moan as well, bucking his hips forward and hitting the back of the dark-haired man's throat.

Pretty soon Dean is thrusting into Castiel's mouth at a rapidly increasing pace, essentially fucking his face. "Fuck…" He throws his head back, arching his spine. "CAS!" He screams the man's name as he explodes into his mouth, then falls back on the bed, gasping and panting. He looks up at Cas, watching his throat move as he swallows. "Damn Cassy, you're pretty good at that. You sure you've never done it before?"

Cas can feel his face heat up.

Dean opens his mouth as if to make some teasing remark but quickly closes it as his eyes go to the visible bulge in Castiel's boxers. He licks his lips, and then, faster than Cas can blink, he is on him. Dean slams into Cas, yanking down his boxers to expose his throbbing cock. He licks his palm, and then wraps his hand around the base, squeezing it. Cas throws his head back, letting out a low moan.

Dean begins pumping his hand up and down Castiel's cock; starting slow, but increasing to a fast, rough pace in a matter of seconds. Pretty soon he has Cas turned into a writhing mess beneath him. The dark-haired man bucks his hips, thrusting up into Dean's hand. His hands grip the sheets, balling the fabric into his fists. "DEAN!" And then he's coming, his eyes rolling back in his head and his mouth widening in a loud cry of pleasure.

As he comes down from his orgasm, he opens his eyes to find Dean staring at down at him, his eyes black from arousal. His eyes fade to green again as he takes two fingers and slowly runs them through the cum pooled on the fallen angel's chest. Without breaking eye contact he brings the fingers up to his lips and begins to lick them, slow and seductive, before taking them into his mouth and sucking them with a low, "Mmm…"

Cas is completely mesmerized by the sight, finding himself unable to look away from the green-eyed man who sits before him, shamelessly sucking cum from his fingers. After licking his fingers clean, Dean grabs Cas by a handful of dark hair and pulls him into a heated, cum-filled kiss. It lasts only a few seconds before Dean pulls away.

He zips up his jeans, then stands and begins to collect his many layers of clothing. "Well Cas, that was a lot of fun. But," he pauses to pull on his t-shirt, "I gotta run." He pulls on his over shirt and jacket, and then disappears before Cas can push through the fog enough to even acknowledge that the other man had spoken.

Castiel flops back on the bed, drunk, panting, and covered in a combination of sweat and his own cum, and passes out.

Maybe passing out hadn't been the best idea, because when Cas wakes up four hours later, it has dried to a sticky crust on his chest. He stands up, too fast apparently because he immediately feels as though he is about to throw up, then quickly sits back down. He lays there for a good five minutes before sitting up, _slowly _this time, so as not to spill the contents of his stomach over the floor. He then hangs his legs over the edge of the bed and pulls himself to his feet, also slowly. He looks down at himself; he's a mess. He's going to need a shower.

After his shower, Cas promptly vomits, dresses, and then vomits some more. His head is pounding and he can't seem to locate the Advil. Sam usually keeps it in the medicine cabinet, right? After digging through the entire medicine cabinet, and emptying its contents onto the floor, he discovers that it is not there. He then moves onto Sam's room and finds it just sitting on the bedside table. It's then that he remembers Sam's frequent headaches (most likely stress related), and wonders how his friend is fairing without the help of painkillers. He takes two of the pills and then goes to lie down.

Maybe drinking so much wasn't such a good idea after all. Now here he is, lying on his bed, feeling like shit and brimming with regret. Then again, wasn't that how Castiel spent all of his time now, regretting past mistakes?

He sighed heavily, rolling onto his side and pulling the blanket over his head. Both his body and mind ached for the release of sleep, but he did not want to dream again, for he feared what his recent actions would bring to his subconscious. So there he lay, fighting sleep with all his might, yet to exhausted to move from his spot on the bed. When did his bed get so comfortable? It's then that he remembers exactly what will help him stay up. _Coffee. _He shakes his head as he sits up, surprised he didn't think of it before. _Thank you, Sam Winchester._

He makes his way to the kitchen and then realizes that he has absolutely no idea how to work the contraption. Luckily Sam had left a note taped to the coffee pot with detailed, step-by-step instructions on how to brew a pot of coffee. As it turns out, it wasn't nearly as difficult as Cas had anticipated it to be, and in about five minutes, he had his caffeinated beverage and was ready to go on with his day.

The coffee really did help to wake him up, and pretty soon Cas was back to work. More research, always research, he was beginning to think that even in the extensive library left behind by the Men of Letters, he would find nothing on the mark of Cain. Of course, the next best idea was to go straight to the source, Cain himself, to see if he knew what to do. But of course, that would be incredibly stupid. There was one other person who knew about the mark, well not a person at all an angel really. The very one who first put the mark on Cain. Yup. You guessed it. Lucifer. Of course that was even more stupid than the last idea. So basically, unless you were willing to either die, or make some sort of deal that resulted in a second apocalypse, there was nothing they could do but let Dean have his way. And yet… and yet Cas knew he couldn't do that, he owed it to Sam to keep trying, even if he'd already given up. And it wasn't just that, in truth he wanted Dean back more than anything, and if he died trying to save his friend, then so be it. At least his death would mean something, unlike the thousands of human deaths that occurred on a day-to-day basis.

Eventually, inevitably, Cas does fall asleep, face down in some old, ridiculously large book that was happens to be the journal of some esteemed demonologist from the 1930s.

His dreams are the sweaty kind, filled with moaning and grinding; his hands running over scarred, freckled skin, before tangling in short, dirty blonde hair; stubble scratching at his skin as those thick, flawless lips worship every inch of his body; soft green eyes meeting his own, before suddenly going black, accompanied by an arrogant smirk.

Cas wakes with a single word on his lips, well more of a moan actually. "_Dean." _He's lying in a puddle of his own drool, and when he sits up, catching a glimpse of his reflection in the reflective glass of the cabinet door, he sees that he has a black ink smudge on one cheek. He's also painfully hard… again.

_Yup. _Cas sighs, running a hand over his tired face. _This might start to become a problem. _


	3. Chapter 3

Just One Yesterday

Chapter 3

So maybe Cas had a bit of a problem... A six-foot two problem with dirty blonde hair, glittering green eyes, and sinfully kissable lips… Okay getting off track here. He'd made a terrible mistake. What he'd done with Dean, It was wrong, he knew that. And yet… and yet he couldn't stop thinking about it, craving Dean's touch like he craved oxygen. But he wouldn't let it happen again, he couldn't. He would be able to resist temptation. But would he really? Somehow he didn't think he'd be able to resist Dean. He cursed himself for being so weak, for being so human.

He sighed, burying his head in his hands. He didn't know what to do. Dean would be back, he knew that, and he couldn't possibly tell Sam, he'd never look at him the same, and the younger Winchester was the only friend he had left. So what then? What was there left to do but give up?

Sam knew something was off the second he saw Castiel. He had only been gone a week, and yet the changes he observed in the personality of the dark-haired man were astronomical. For one thing he was jumpy, constantly on edge, although that could be blamed on the copious amounts of coffee he had been drinking. He also didn't seem to be sleeping anymore, and when he did, it was never for long, although occasionally he would fall onto whatever piece of furniture was nearest for a three or four hour nap.

On one such occasion Sam walked into the bunker's living room to find Cas curled up on the couch, muttering to himself in his sleep, he couldn't quite make out what he was saying but he could tell that some of the words were definitely not English. Enochian probably. It was when Cas let out a low whimper that Sam decided it was best to wake him up, but when he did, Cas' blue eyes shot wide. His face reddened upon seeing there and he quickly excused himself, mumbling something about needing to go take a shower.

And then of course there was the drinking. Sam had pretended not to notice how the bunker's supply of "Hunter's Helper" was being quickly depleted, though he knew he wasn't the one responsible.

It became obvious that something had happened while he was away, though of what it could be Sam was unsure. All he knew was that Cas wasn't interested in talking about it, and he didn't want to pry. There were after all, more pressing matters at hand.

Cas let out a long, low moan, bucking his hips up into Dean's mouth. He looked down at the demon, reveling in the way his thick pink lips spread around the length of his cock. He Dean looked up at him, his green eyes bright against dark lashes. Cas was lying on his back, cursing in Enochian as he balled the sheets up into his fists. Dean hummed, a low vibration in the back of his throat that Cas felt throughout his entire body. He threw his head back in a long whimpering whine.

"Cas?" The voice seemed to come from nowhere. "Cas! Wake up!"

Cas' eyes shot open and he found himself laying on the couch in the bunker's living room looking up at Sam who was frowning in concern. "Cas man, are you okay? You were mumbling in your sleep."

Cas stared blankly at Sam. Mumbling? He was suddenly very glad that the pleasantries of his dream had caused him to revert to Enochian. "Yes." He stuttered. "I-I'm fine."

"Are you sure?" Sam asks. "You don't look so good."

Cas shakes his head, as if to clear it. "I'm quite alright Sam, I just…" He pauses. "I'm going to go take a shower."

Before Sam can respond, Cas stands, and all but flees in the direction of the bathroom.

In the shower Cas lets the hot water run over him, rolling his shoulders to rid them of the stiffness that built up there over the course of his nap on the less-than-comfortable couch. He can't help but reach down and begin to slowly stroke the length of his throbbing cock, as his thoughts go to Dean.

Thoughts of what it would be like, lying on his back, with Dean's weight on top of him; Dean's heat surrounding him; Dean's hardness pressing inside of him. He lets out a low moan as he begins to pump his hand faster and faster, until suddenly, with a sharp yelp of "_Dean!"_ He spills his load onto the tiled wall of the shower.

He leans his head forward, resting it against the wall and breathing heavily. With one hand, he splashes water onto the wall rinsing away the mess he made.

He lets out a short, shaky breath, a bit like a laugh. He wasn't aware that it was possible to be this addicted to another being, to crave their touch constantly, and above all else. To want them, no matter what sort of horror they committed, no matter what they became. And above all else, to be unable to stop, no matter the consequences. Yes, it would seem Dean Winchester was more of a drug then a person, or demon, if you wanted to be more accurate. Either way, Dean was like heroine. And Cas was hooked.

The days passed by and the knots of dread and anticipation in Cas' stomach seemed to worsen each minute that passed. He knew Dean would be back, and the prospect filled him with a combination of excitement and horror. It had been almost two weeks now, and he was beginning to think Dean was doing this deliberately, just to mess with him. Of course, he was a demon, and that's what demons did. They played games. Sadistic, cruel games, they reveled in whatever pain they could cause. Dean was no different.

Castiel lay awake in bed, staring up at the ceiling. He's not sure how long it's been since he told Sam he was going to bed. Minutes maybe? Or was it hours? All he knows is that the younger Winchester has long since retired for Cas can hear his soft snores through the thin walls of the bunker.

But Cas is not tired. Or maybe he is, maybe he's just afraid of sleep, of dreams haunted by a man with eyes the colour of spring.

He sits up, rolling out of bed and heading towards the living room. Maybe a bit of television will help him to clear his mind. He sits down on the couch and turns on the television to some of the humorous cartoons he has grown to love. He chuckles quietly to himself as yet another of the coyote's elaborate and nefarious schemes to capture the roadrunner becomes turned around on him.

Suddenly the television begins to flicker, emitting loud static sounds as it jumps through channels before turning off with a sharp click.

He hears a low chuckle from behind him, followed by an "Awesome."

"Hello, Dean." Cas replies without turning.

"Wow Cas." Dean hops over the back of the couch, sprawling out with his legs spread and his hands resting between his thighs. "You didn't even jump this time, I'm impressed."

When Cas doesn't respond, Dean breaks the semi-awkward silence. "I can also make the lights explode." He grins. "But I figured that would be a bit over-dramatic." There's a light, teasing undertone to his voice and Cas knows that he is remembering the day they first met.

The fallen angel sighs. "Why are you here, Dean?" Dean lifts his head from where it rests on the back of the couch, turning to look at Cas. He smirks. "You know why."

"Dean." Cas says, moving away from the man and pressing himself against the arm of the couch. "What we did… it was a mistake."

Dean rolls his eyes, moving across the couch and sitting so close that their thighs touch and Cas can smell the mixture of whiskey and old leather with an undertone of sulphur. "Oh don't give me that crap Cas!" He leans in, his voice a low growl that tickles the dark-haired man's ear. "You and I both know that there's not a day that passes that you don't think about it… _dream_ about it. You barely sleep because you know that when you do, I'll be there, whispering all those filthy things in your ear. Face it Cas, you can't get enough of me."

Cas jumps to his feet. "That's not true!" He spits. "You're a demon, a vile disgusting mons-"

He's cut of as Dean grabs his arm and yanks him forward into his lap, kissing him roughly. He nips at Castiel's bottom lip as he pulls away, causing the human to let out a small whimper. "What was it you were saying about disgusting?" He licks his lips.

Cas turns his head away, but Dean grabs his jaw and turns it back, his other hand sliding down his back and settling just above his ass. "Dean no." Cas gasps as Dean's hand slides down a bit further, sending shivers down his spine.

"C'mon Cas." Dean nips at his earlobe. "I know what you really want. It's coming off you in waves, the desire, the…" he pauses, planting a kiss just behind his ear, "_need. _You couldn't resist me even if you wanted to Cas." Another kiss, on his jaw line this time. "And you can lie to Sam, hell you can even lie to yourself." His lips moved further down the fallen angel's neck. "But you can't lie to me." He breaks the kiss and stares into Cas' face, his pupils blown with lust. "I can see inside your head Cas, I know what comes to mind every time you think of me. All the things you want me to do to you…" He bites his lower lip. "So you have two choices here, you could tell me no, run and hide away in your room, and go back to spending every night dreaming about what it would be like to let me fuck you…" He trails off, raising his eyebrows. "Or you could stick around long enough to learn that the real thing is _so _much better than a dream. It's your call." He squeezes Castiel's ass through the fabric of his boxers, causing the dark-haired man to let out a sharp gasp. "So what'll it be angel."

Cas leans forward, pressing all of his weight against Dean's chest and kissing him without restraint. His hand tangles in the demon's sandy blonde hair as their tongues explore each other's mouths. Eventually they have to pull away to catch their breath, but they stay with their foreheads resting together, Cas can feel Dean's warm breath on his face.

"Thought so." Dean grins, sliding his hand slowly up the back of Castiel's shirt, his nails digging into the skin there, drawing a shuddering gasp from the man straddling his lap.

Dean then drops the hand down to join the other on the man's ass, tugging him even further into his lap. The dark-haired man moans at the friction of the denim against the thin material of his boxers, his hips rolling automatically in search of more. Dean responds by pulling Cas even closer and rolling his hips up so they meet.

The demons hands tug insistently at the hem of Castiel's shirt, and the kiss is momentarily broken as it is pulled up over his head. Dean's fingers trail over the Enochian warding symbols tattooed across Cas' ribcage. The former angel shudders at the contact, causing Dean to chuckle, the sound a deep rumble in the back of his throat.

Dean positions his hands on Cas' waist, before flipping him over so he lies flat on his back with his head resting against the arm of the couch. Cas gasps, temporarily awed by the speed and fluidity of the movement. It serves as a reminder of just how much power runs through Dean. He is a demon born of the mark of Cain, more powerful than Crowley, more powerful than Abbadon, virtually unkillible except for with his own blade, which could only be used by two demons in all of existence, one of which was Dean himself. Dean Winchester was among the most powerful enemies they had ever gone up against, and they had gone up against some big fish. And here was, hovering mere inches from Castiel's face and brimming with a strength that the fallen angel could hardly contemplate. It was oddly surreal. All of this was forgotten as Dean's lips met hungrily with the skin of his partner's neck.

Castiel gasps sharply as Dean's stubble tugs at his skin a little and his hips buck of their own accord as the blonde sucks at the spot just below his collarbone leaving a small red welt. Dean kisses a trail down Cas' chest, grazing his teeth over the dark-haired man's nipple. Cas shudders beneath him, whimpering softly. Dean clearly finds this encouraging because seconds later he sinks his teeth into the side of Cas' pectoral muscle, clapping a hand over the other man's mouth just in time to muffle the sharp cry that escapes him.

"Shh, Cas." Dean chuckles against his skin. "We wouldn't want Sammy to wake up and spoil our fun now would we?"

Cas lets out a small whimper, shaking his head. No, of course he wouldn't want anything to ruin this. The mere thought of Dean taking away the pressure of their bodies together is almost painful.

"Then shut it." Dean grins up at him, before returning his lips to Castiel's chest. Cas bites his lips to hold in the noises that threaten to escape him, but when Dean's mouth returns to his nipple, rolling it around with his tongue, he begins to produce small whimpers. Dean seems to take this as encouragement, because seconds later he pinches the peaked skin of the dark-haired man's nipple between his teeth causing Cas to tense up beneath him, letting out a sharp yelp.

Dean sighs bringing his head up so his breath tickles the fallen angel's ear as he speaks in a low, breathy voice. "I think it's time to move our little party elsewhere. My old room, it's far enough away that Sam won't be able to hear us, although you might need to bite the pillow, because babe I plan on making you scream tonight."

The words make Cas shudder, his arms tightening around Dean's torso as he nods in affirmation, letting out a small noise of agreement, he's already too far gone to really care. Dean attempts to pull away but Cas tightens his grip around him. Dean rolls his eyes. "So that's how it's gonna be, huh?" He hooks his arms under Castiel's knees, pulling him up so he hangs off the front of him, like a reverse piggyback. "You know Cas, you are really lucky that seeing you come undone like this is possibly the hottest thing ever." He pauses, throwing his head back in a short gasp and Cas nips the skin on the side of his neck. "Otherwise you'd probably be dead already." That causes Cas to freeze temporarily, as he suddenly realizes how dangerous the game he's playing really is, however a sudden squeeze of his ass from Dean, has him gasping again, and his lips return to the demons neck.

The fallen angel doesn't remember much of the journey from the living room to the bedroom, his attention focused on the man carrying him more than anything else. Every part of him is on fire, it radiates through his blood like an itch he can't scratch. It's not until he hears the door close that he realizes they have reached the room at all. Dean, still holding Cas up against him, slams the other man up against the newly closed door, causing him to gasp sharply against the blonde's neck.

Dean presses his lips to Cas' so hard that their teeth knock together. His tongue forces it's way into the other man's mouth, trying to explore every corner. Cas tightens his legs around Dean's waist, tangling one hand in the demon's hair as he clings to him. "Cas," Dean gasps, throwing his head back. "I'm gonna fuck you so hard you can't walk straight for a week."

"Dean," Cas gasps breathlessly as he grinds their hips together, desperate for friction. Dean whirls them around and seconds later they're falling backwards onto the bed, Cas' legs still firmly wrapped around Dean. They stay this way, Dean's lips latched onto Cas' collarbone as they grind together, each trying to suppress their low moan and gasps in the hopes that Sam won't hear.

When Dean pulls away to remove his own shirt and jeans, Cas whimpers a little at the loss of contact, but Dean is on him again only seconds later, and they're kissing and grinding together all over again.

Dean hooks his fingers into the waistband of Cas' boxers, pulling them off of him and tossing them somewhere behind him. Dean's come off just as quickly, and soon the two are rutting against each other, their cocks sliding against one another causing Cas to gasp at the heat of the contact.

Dean pulls away again, this time positioning his hands on Cas' hips and flipping him over so he lies on his stomach. He spreads the dark-haired man's legs and sits down between them, before leaning over to the bedside table and pulling a small bottle of lube out of the drawer. He opens it and carefully coats on finger in the clear liquid, using one hand to spread Cas' ass cheeks he trails the finger teasingly around the man's entrance. Cas gasps at the contact and involuntarily presses back into the finger, which causes Dean to pull away teasingly. Cas lets out a low growl of frustration, but Dean just chuckles in response. "Damn Cas, eager much?"

Cas turns to look at Dean, to see the demon smirking at him, green eyes glinting mischievously. "Dean," Cas gasps. "Please."

Dean lets out a low chuckle in the back of his throat before sliding the finger in up to the first knuckle. Cas lets out a low moan as the finger slides deeper into him. Dean begins to pump the finger in and out of the dark-haired man's ass first slowly, but gradually speeding up. He adds a second finger and soon he has Cas moaning and pressing back against his hand as his eyes roll back in pure ecstasy.

"Mmm Cas," Dean leads forward so that his lips brush the other man's ear as he speaks. "I bet you could come just like this couldn't you, such a little cockslut."

Cas lets out a string of Enochian curses followed by a muffled "_Dean"_ into the pillow as Dean crooks the fingers slightly before driving them further into his ass.

"I'll take that as a yes." Dean chuckles, pulling himself back up into a sitting position. "We'll have to save that for another time though. Because tonight, that tight little ass of yours is _mine._"

Dean pulls the fingers out and picks up the bottle of lube, depositing a glob into his palm before slowly beginning to run his hand over his own length, letting out short, gasping moans as he does so. Castiel watches in awe as Dean throws his head back, his mouth falling open and his eyes closing as he jerks himself, slowly, almost teasingly, until Cas finally can't help the small whimper of "_please" _that escapes his lips.

Dean chuckles, his eyes opening as he looks down at Cas, raising his eyebrows in a taunting question. "Please what, Cas?"

Cas sighs before turning to look over his shoulder at Dean, blue eyes wide and pleading. The demon stares down at him, smirking expectantly. He's really going to make him say it isn't he.

The former angel buries his face in the pillow to hide the redness he can feel spreading over his cheeks. "Fuck me." The words are muffled by the fabric covering his mouth, but still understandable.

"Almost." Dean bites his lips, staring down at the dark-haired man spread out before him. "But I think you can do just a little bit better than that."

Castiel growls in frustration, lifting his head to look at the man behind him. "What do you from me?"

Dean leans slowly over him once more, getting close enough that Cas can feel the heat of the other man's skin just centimeters from his back as whispering lips brush softly against his ear. "I want you to tell me exactly what you want me to do to you." His voice is a low, gravelly whisper, the kind that sends shivers down Cas' spine. "I want you to beg for me, _Angel, _I want you to tell me how badly you need this and I want you to look at me while you do say it." A seductive grin spreads across his perfect lips as he stares down at Cas, waiting for the angel to respond.

"Dean," Cas begins, chewing his lower lip as the heat once again creeps across his cheeks. He can't believe he's doing this; then again he can hardly contain his arousal at the prospect of Dean entering him. "I want- no, I need, for you to… to fuck me. _Please." _The last word comes out as a pleading whine, and Dean's eyes immediately darken.

"Of course Cas." His tone is a taunting one, but his arousal is visible in every aspect of him. He lines himself up with Cas' entrance before slowly pushing in past the first ring of muscle.

Cas gasps sharply as Dean pushes himself further and further into him. At first it hurts a bit, but soon the pain subsides into a deep, throbbing pleasure. "Fuck, Cas!" Dean's words are barely audible between his heavy breaths. "You're so tight."

"Dean!" A string of Enochian curses falls from the dark-haired man's lips as Dean pulls out, before thrusting back in, starting slow, but quickly adding speed and power to his movements. Cas has to bury his face in the pillow to muffle the moans escaping him as Dean pounds into him, hitting his prostate on every thrust.

"Oh Cas," Dean growls in his ear. "Listen to you, you're loving this. You're one filthy little angel aren't you." Dean nips at his earlobe, thrusting again, this time so hard it almost hurts. Cas has to bite down on the pillow to stifle a scream. "I bet you could come just like this, couldn't you?" Dean continues, his voice dropping a register. "Bet you don't even need a hand on your dick. Such a good little cockslut." He slams into the other man again, and Cas can feel heat building in the pit of his stomach.

Dean thrusts into him again and again until Cas feels as though he's going to explode, in the next second he comes, spilling his load onto the mattress beneath him and biting down on the pillow to hold back a cry as an intense wave of pleasure washes over him. He clenches around Dean's dick, and seconds later he is coming too, filling Cas up.

Dean collapses on top of Cas' back, panting heavily. "Some angel you are." He chuckles as he catches his breath, before pulling out slowly. Cas hisses at the slight sting, before relaxing once again.

Dean rolls off of Castiel, still panting heavily, his chest rising and falling dramatically with every breath. "Damn Cas," He laughs, but it comes out as more of a wheezing sound between his heavy breaths. "You sure you've never done that before?"

Cas rolls on his side to look at Dean, frowning in confusion. "Not within my memory, no."

Dean laughs again, though Cas is not entirely sure what he finds so humorous. He shakes his head. "I missed that."

"Missed what?" Cas tilts his head to one side, it's as if, for a moment, he can see beyond the demon to the man he once was. But then Dean grimaces, as though realizing what he said, and turns away.

"Well Cas," He says, sitting up and arching his back, the skin stretching over the muscles of his chest. Cas can here a few popping sounds as the vertebrae move back into place. "This was fun but," he pauses to pull his discarded shirt over his head, "I gotta run." Before Cas can respond he's gone, leaving the other man lying in a sticky mess and breathing heavily.

Suddenly Cas is tired, so tired. He leans his head back onto the pillow, wanting so badly to drift off. It's then that he realizes that he is surrounded by evidence of his recent encounter with Dean, and has only a few hours until Sam wakes up. He drags himself into a sitting position, sighing heavily.

He first goes to the bathroom to clean himself up, as there his stomach is largely encrusted with his own cum. He finds himself thanking some higher power that the bunker's washroom is far enough from Sam's room that he will not hear. After his shower, he locates his clothes, left both in the living room and Dean's room after being hastily discarded, and dresses. He strips the sheets off the bed and throws them in the washing machine. He grabs some fresh sheets from the closet (all of the sheets in the bunker look the same anyway) and makes Dean's bed. After this is finished he sits down in to watch some TV while waiting for the sheets to be clean. He flips the sheets over to the dryer and goes to bed.

When Sam awakes the next morning at nine o'clock, Cas is still asleep. It's not all that unusual so he disregards it and makes coffee, knowing Cas will probably want some when he wakes up. However the hours tick away and the coffee goes cold before Cas is even up, Sam stands to reheat it. When Cas finally does stumble out of his room, it's past noon and a he looks half asleep, his hair sticking up all over the place and his clothes still rumpled.

When Cas woke up it felt as though he'd slept for years, but also hadn't slept at all. He rolled over and checked the clock. Twelve fifteen. He sits up in shock, suddenly realizing how sore he is from the previous night. His ass throbs dully, reminding him of his late night visitor. He rubs at his eyes to wipe away the sleep. "Dammit." He mutters to himself, before rolling out of bed and heading to the kitchen.

"Mornin' Cas." Sam greets.

"Good morning to you as well Sam." Cas runs his fingers through his messy dark hair. "Is there coffee?"

"Yeah." Sam grins. "Figured you'd want some."

Cas grabs a mug and fills it with the dark liquid before adding milk and sugar as well. He takes a sip, savouring the heat and the flavour before sitting down across from Sam.

"So," The taller man begins. "Late night?"

Cas freezes. He knows, he must know, maybe he heard them or… "Why do you ask that?"

"Well you look like hell, and you slept past noon." Sam says it like it should be obvious.

"Oh." Cas says. "Yes, um, I found it rather difficult to fall asleep last night."

"Yeah, I get that." Sam laughs. "By the way there were some sheets in the dryer, are those yours?"

"Oh, um…" Cas trails off, he hates lying to Sam, but he has to think of some excuse. "Yes, I found that the sheet was unclean, the dirt irritated my skin, so I changed it." He pauses. "My apologies."

Sam frowns. "You don't need to apologize, there's nothing to be sorry for."

"Of course." Cas looks down. "Nothing at all."

And so that's how it goes, Dean showing up whenever he felt like it pinning Cas to a wall or throwing him down on a bed, and taking what he wanted. The sex was good, fantastic actually, but he was lying through his teeth to Sam on a day-to-day basis and he didn't know how much longer he could keep this up.

One day Sam had almost caught them. It had started out like any other day; Cas was walking down the hallway when suddenly he felt a strong grip on his arm and the next thing he knew he was pinned up against the wall in a supply closet.

"Hey Angel." He had felt Dean's smirk against his mouth as there lips were pressed together, tongue forcing it's way between Castiel's lips before he even knew what was happening.

"Dean," Cas lets out a small moan as Dean's fingers tangle in his dark locks, tugging slightly. "Sam he could- Ah!" He let's out a sharp gasp as Dean's teeth rake the side of his neck. "He could hear us."

"Relax." Dean says between kisses on Cas' jaw line. "Sammy's in the shower, we have some time." He smiles seductively, before placing both hands on Cas' shoulders and shoving down hard so that the other man falls to his knees.

Cas looks up at Dean, temporarily shocked by the speed of the movement, but then his body takes over and his hands go to the buttons on Dean's jeans. "Someone's in a hurry." He taunts.

"Mmmhmm." Dean hums, tangling on hand in the other man's thick dark hair. "Gotta make this quick Cas, I'm a busy man… or demon I guess." He chuckles slightly at his own words, tugging Cas' hair and pulling him forward slightly.

Cas finishes undoing Dean's pants and pulls out his already half hard cock. He strokes him to fullness, before swallowing him down without hesitation. Dean lets out a low moan, thrusting his hips forward. Cas would have gagged had he not been pulling back. "Fuck baby." He rolls his hips forward again. "You're such a good little slut. So fucking good." He tugs again on Cas' hair. Cas lets his jaw go slack; allowing Dean better access as the demon virtually fucks his face. Seconds later Dean is coming, long ropes of it shooting into the fallen angel's mouth. Cas swallows it all down and then pulls off of Dean's dick with an audible pop.

The hand in Cas' hair tightens and he's dragged back to his feet and into a sloppy, heated kiss. He can feel Dean's tongue exploring every inch of his mouth, almost forcefully. His hand goes to Castiel's zipper, pulling it down slowly before dipping his hand under the waistband of his boxers and gripping his hard dick around the base.

Cas moans against Dean's lips as the other man rubs his thumb over the head, his hips jerks forward, fucking up into Dean's fist. "Dean!" He pants softly against the other man's lips.

"Come on baby." Dean nips at Cas' neck. "Come for me."

And that's all it takes, Cas bites down on Dean's shoulder to hold back a cry as he comes all over the other man's fist and the inside of his boxers.

"Gotta run." He tucks himself back into his jeans. He pulls Cas in for one last kiss, one last messy, rough, _incredibly hot _kiss. He tugs the other man's lower lip between his teeth as he pulls away. "But I promise I will pay you back for that blowjob later." The tone of Dean's voice sends shivers down Cas' spine. Then Dean's gone, and Cas is left alone in the supply closet.

He does up his pants and stumbles out of the closet, squinting against the sudden light.

"Cas?" Cas turns to see Sam coming down the hallway, wet hair hanging in his face. "What were you doing in the closet?"

Cas stares at Sam with wide eyes, hit with the sudden realization of how he looks currently. Hair messy, lips swollen, not to mention the unpleasant stickiness in his boxers, though he's fairly certain Sam knows nothing of that. "I um…" He begins. He realizes then that he can't think of a good reason for that. "I was looking for… It's not of import. I am going to go take a shower now."  
"Um… okay." Sam frowns after Cas in confusion as he races off in the direction of the bathroom.

That was far too close for his liking. If this keeps up, Sam's going to figure it out. He thinks again, that it would be best to end this whole thing, but his mind drifts back to the way Dean had whispered in his ear, the promise to return the favour, and he realizes once again how badly he needs that shower.


End file.
